They should repair it under warranty, period. If they cannot make a return label, you can send it back. IIRC they are also responsible for the shipping cost, but they can refund it afterwards when they are not able to create a return label.
I think your mistake might be that they are sticking to the letter of the law. Don't ask for your 14-day cool-off period, because strictly I think the product needs to be sealed (though many sellers are more lenient):
Instead ask for a repair under warranty, which they are required to do as a seller. They cannot point you to the manufacturer, the seller is responsible for handling warranty for the first two years:
I think your mistake might be that they are sticking to the letter of the law. Don't ask for your 14-day cool-off period, because strictly I think the product needs to be sealed (though many sellers are more lenient):
https://business.gov.nl/regulation/cancellation-period-sale/
Instead ask for a repair under warranty, which they are required to do as a seller. They cannot point you to the manufacturer, the seller is responsible for handling warranty for the first two years:
https://eur-lex.europa.eu/EN/legal-content/summary/product-g...